I've recently been considering the possibility of adding an aftermarket overdrive unit to my 75 SuperCab. However, since I'm not really up to date on the cost or even the labor considerations on what's available out there. I thought that I might be able to get some information, advice and/or maybe even some good recommendations about what direction it would be best for me to persue.

Here's some information about my truck:

1975 F-250 4x2 SuperCab "Ranger"
80.55" Short Bed w/138.8 Wheelbase
460 Engine w/C-6 Transmission
Current Mileage = 11.5 MPG

The main areas of information that I'm interested in finding out about this undertaking are:

What types of overdrive units are avaliable for my pick-up?

What are the pro's & cons associated with these units?

What are the associated costs involved with this type of an upgrade?

What type of technical & labor considerations are involved with this type of a project?

Will the anticipated increase in miles per gallon be enough to eventually make this a cost effective effort?

Are there any other acceptable methods available that are more cost effective than adding an overdrive unit that will substantially increase the miles per gallon I'm getting with this engine?

Just let me know if you need any additional information about my truck & I'll get it posted as soon as I possibly can!

Many thanks in advance for any information, advice and or opinions provided in response to this inquiry. Any assistance provided will be gratefully accepted and sincerely appreciated!

75 SuperCab

 

gear vendors $ 2,695 +$650 to install with new driveshaft save about 20% on gas.I have looked at it everyway you can .I can buy alot of gas with $3,345.but the gear splitting is cool option. info @gearvendors.com good luck I passed on it.

 

You could change to a higher rear axle ratio and/or larger diameter rear tires if you do mostly open road driving. But 11.5 isn't bad for a 460/C6 combo. Don't know how much better mileage you'll get no matter what ratios you use. It's a heavy truck with a big motor. My '77 SC 150 long W.B. only got about 16 mpg hwy with a 300-6 and 3spd manual.

 

11.5? wow. i get 7mpg in my 79 4x4 w/ a 460 and a 4-speed. its a little warmed over, but not enough to be getting only 2/3 what you are! is the 4x4 really that much of a drag?

justin

 

Gear vendor, E4OD with a stand alone ECM to make it work, or Lentech AOD. None are cheep Gear vender would be the easiest, if you could find a good used E4OD cheep the controllers are 1000.00 to 1500.00 that might be the cheepest way to go. A Lentech is about 3500.00.
Leadmic

 

I didn't know that there was a stand alone ECM available for the E40D. Where do you get it?

 

Baumann makes one I guess I was wrong on the price they list one for $550.00. Their was someone else making one also but I cant remember the name of the company. I would post the web address but I dont think it would make it on to this post unless they are a sponser. Just google Baumann it should come up.
Leadmic

 

get the e4od and search for a control unit

 

The Baumann ECU unit seems to pretty simple to hook up. Just have to figure out how to calibrate with a computer. I have not done this yet, but I am really leaning toward doing it. I have a 77 F250 4x4, 460 (521 stroker) which I'm waiting on my parts and the cab to get redone so I can start putting together this winter. I can't use the gear vender unit on a C6 since I have the divorced transfer case which I want to keep, So I'm looking at the E40d with the stand alone CPU. I posted a thread in the tranny forum and have gotten no replies to anyone who has done this. Between the E40d rebuilt tranny and the stand alone CPU, and wire harness, I'll probably have around 1500 to 2000 bucks in it. I don't need a performance tranny because my engine is not going to be for racing, just a little bit more cubic inches to have a bit more HP If the stand alone CPU works, I really dont see any problems installing the E40d except the front driveshaft to the transfer case will have to be custom built. Good thing I'm using aluminum heads to lighten the front end a bit, because those E40d's are heavy.

I believe someone had posted a tech article for putting in an AOD tranny in his 79 bronco. I believe he had an AOD performance rebuild and had around 3500 in his project.

If anyone has used the stand alone CPU and an E40d. let me know how you like it.

 

Is there not a way to "trick" the stock ECU to work? Does anyone know what inputs the ECU is getting form something other than the transmission? it propablly is looking for a voltage input from a sensor, or multiple sensors, which should be easy to fake. Making it tunable could be difficult, which is what Baumann has done. Anyone know the cost of the Baumann unit?

 

Search the transmission forum, E4OD and Bauman are covered quite often. It's not a difficult swap but the 4x4 adds a degree of complexity that I can't comment on. I have done this swap on my '76 F100 2wd two years ago.
You need an earlier E4OD, '92 or older if I remember correctly. It needs to have the speedo cable with the sensor at the drive gear. Newer trucks had fully electronic speedo with pickup on the pinion gear of the rear end (or you could swap rear ends?). More importantly is the fact that the newer E4ODs do not have the drive gears for the speedo cable on the out put shaft.
It is a big transmission, bigger than the C6 it's based on. It's a tight fit, very tight fit and you will have trim the housing a bit as well as fab a crossmember and shift linkage. And get your drive shaft shortend.
You will need to hook a Throttle position sensor to your carb.
A stock ECM, or correctly EEC does engine and transmission so its not feasible on a carbed engine. Of course you could swapp the entire drive train but thats a bit more than what was asked here..
I still may have some pics in my gallery. Gas mileage improves on the highway for sure but as stated a lot depends on your tire size and rear end ratio and the way you drive!
Check Bauman website for pricing and info $550 sounds right, with a interface cable a little more.
Much cheaper than gear vendors!

Frank

 

If you do the math it really takes a long time to pay off if at all.

 

It would take a long time to pay off when you think of gas mileage savings, but I am more interested in saving on wear and tear. I don't want to have to change gear ratios in my rear end (which would not do much anyway) to lower my RPMs at speeds of, oh like 70-80 mph down the interstate. Short drives at that speed with a C6 won't do much, but when I have to take the truck on an 8 hour drive, that's alot of wear and tear on an engine and also much more gas. Plus I want to be able to hear my radio when cruising at 80 mph down I -90. I really don't know for sure how the truck will react with an E40D, but I would think much better than a C6 as far as RPM and MPH.

 

Changing the axle ratio can be cheap if you go about it the right way.

I timed my last ratio change with a rear brake job. I found another complete rear end in the ratio I wanted - with decent brakes. Spent $250 CDN on the whole operation.

 

Hes not talking about just the rear end. He has a 4X4 and the front end is a lot more work to change the gears on than the rear end is.
Leadmic